The present invention relates to methods of bonding components and more particularly to low temperature methods of bonding components and related structures.
It is known to bond components such as microelectronic devices to a substrate using solder reflow as discussed, for example, by E. Yung et al. in “Flip-Chip Process Utilizing Electroplated Solder Joints” (Proceedings of the Technical Conference, 1990 International Electronics Packaging Conference, Sep. 10-12, 1990, pp. 1065-1079). Flip-chip technology (also known as C4 technology) relies on gang bonding of bumped pads to a substrate with a matching footprint. SnPb solder of high lead content can be used as the bump material. The bonding mechanism is the wetting of pad metallurgy during thermal reflow of solders. The disclosure of the Yung et al. reference is hereby incorporated herein in its entirety by reference.
Reflowing solder, however, means that the solder is heated above its melting temperature, and one or both of the substrate and/or the component may also be heated above the melting temperature of the solder. In some applications, excessive heating of the substrate and/or component may not be desired. In addition, the reflow of solder may result in the outgassing or evolution of materials such as flux which may leave an undesirable residue on the component and/or substrate.